The first thing to do is to establish what the expectations are in legal terms. My impression is that tour operators/sellers must refund in full if that is what the customer wants - but you need to ensure that is what you can reasonably demand. Citizen's Advice, googling sensibly, etc. should get you to a reliable understanding. Were it not for Covid, operators cancelling flights originating and/or ending within the EU would automatically lead to a right not just to a refund but also compensation of hundreds of euros per person per leg - these days Covid inspired cancellations guarantee a right to a refund. The accommodation element (food and transfers too) are a separate element which I am not 100% certain about. If you have paid by credit card there is a separate/additional level of money back guarantee that may be available to you over any amount paid that way - check with the card issuer.
Choosing a refund rather than a voucher (even one boosted by a "bonus" element) makes sense because the voucher replaces the right to a refund, and if the operator subsequently goes bankrupt or simply closes then the voucher is worthless and there is no comeback.